• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.5
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• pp.245-249
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• 2006

This study tries to test and analyze the static friction torque generated by an electromagnetic clutch. Then the torque is improved by optimizing the shape of armature. For the purpose of design change and optimization of the electromagnetic clutch, the static friction torque prediction is very important. We construct an axi symmetric FEM model for analyzing the static friction torque and used a torque tester for evaluating the real torque. For a test, predicted static friction torque is compared with the experimental one to discuss the rationality of torque analysis process. The analytical result agrees well with experimental data, explaining the validity of the mathematical process and FEM model. After confirming the torque analysis process, the optimization process is investigated. The optimization result shows that the static torque is improved by changing the armature shape.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.8 s.239
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• pp.1051-1060
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• 2005

Nonlinear Response Optimization using Equivalent Static Loads (NROESL) method/algorithm is proposed to perform optimization of non-linear response structures. The conventional method spends most of the total design time on nonlinear analysis. The NROESL algorithm makes the equivalent static load cases for each response and repeatedly performs linear response optimization and uses them as multiple loading conditions. The equivalent static loads are defined as the loads in the linear analysis, which generates the same response field as those in non-linear analysis. The algorithm is validated for the convergence and the optimality. The proposed algorithm is applied to a simple mathematical problem to verify the convergence and the optimality.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1316-1321
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• 2003

The systematic method to construct equivalent static load from the given dynamic load is proposed in the present study. Previously reported works to construct equivalent static load were based on ad hoc methods. They may results in unreliable structural design. The present study proposes a selection scheme of degrees of freedom(d.o.f) for imposing the equivalent static loads. The d.o.fs are selected by Two-level condensation scheme(TLCS). TLCS consists of two two-steps. The first step is the energy estimation in element-level and the second step consists of the traditional sequential elimination precudure. Through several numerical examples, the efficiency and reliability of proposed scheme is verified.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.3
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• pp.90-96
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• 1998

The self-excited oscillation is the phenomenon which can be observed in the systems composed of nonlinear elements. The phenomenon is of fundamental importance in nonlinear systems and, as far as the design of a nonlinear system is concerned, it should be considered along with the stability analysis. In this paper, the oscillation of a system controlled by a static nonlinear fuzzy controller is theoretically addressed. First, the describing functionof a static fuzzy controller is derived and then, based on the derived describing function, self-excited oscillation of the system controlled by a static fuzzy controller is predicted. To obtain the describing function of the static fuzzy controller, a simple struture is assumed for the fuzzy controller. Finally, computer simulation is included to show an example where the describing function given in the paper is used to predict the self-excited oscillation of a fuzzy-control system.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.1
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• pp.107-119
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• 1993

The objective of this study is to analyze the static and dynamic characteristics of automotive rubber components by computer simulation. Bush / rectangular type engine mounts and wind shield weather strip are analyzed by using the commercial code ABAQUS and the results are verified by experiments. Large deformation static response is analyzed in order to get the information about the deformation pattern and static stiffness of engine mounts, and about the seperation force of wind shield weather strip from body. The isothermal steady-state dynamic response of components which have been subjected to an initial static pre-load is analyzed for the dynamic stiffness of engine mount rubber components. There are good agreements between simulation and experiments. So it is possible to apply the computer simulation to the design of automotive rubber components.

• Journal of the Korea Society of Computer and Information
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• v.20 no.8
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• pp.69-75
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• 2015

Nowadays, software plays various roles in applications in wide areas. However, the security problems caused by software vulnerabilities increase. So, it is necessary to improve software security and safety in software execution. In this paper, we propose an approach to improve the safety of software execution by managing information used in software through static data access analysis. The approach can detect the exposures of secure data in software execution by analyzing information property and flows through static data access analysis. In this paper, we implemented and experimented the proposed approach with a base language, and verify that the proposed approach can effectively detect the exposures of secure information. The proposed approach can be applied in several areas for improving software safety by analysing vulnerabilities from information flows in software execution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.947-948
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• 2010

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.71-78
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• 2005

In performance-based design methods, it is clear that the evaluation of the nonlinear response is required. The methods available to the design engineer today are nonlinear tim history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. The nonlinear time analysis is the most accurate method in computing the nonlinear response of structures, but it is time-consuming and necessitate more efforts. Some codes proposed the capacity spectrum method based on the nonlinear static analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. The nonlinear direct spectrum method is proposed and studied to evaluate nonlinear response of structures, without iterative computations, given by the structural linear vibration period and yield strength from the pushover analysis. The purpose of this paper is to compare the accuracy and the reliability of approximate nonlinear methods with respect to RC dual system and various earthquakes.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.7
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• pp.75-81
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• 1993

In this paper, New type of Static Edge Triggered D Flip-Flop Circuits which are effective for the sequencial selecting and addressing of Matrix type Electrodes being applied to Flat Display Devices is proposed by the Design Technique using the Transmission Characteristics of Feedback Transistors and Charge Back Up Function. These Circuits composed of 2-4 less transistors in number than Conventional Static D Flip Flop's have some advantages that the Maximum Transition Time of Clock Signals allowed is increased by 100-450 times more than that of the Conventional circuit at 100KHz Clock Frequence and Circuit Safety is much increased by making the wider ranges, 1-4V, of Clock Levelas a Non-operating periods than 3-3.2V ranges in case of the Conventional Circuit at 10MHz clock frequence. By these advantages, These circuits can be very effectively used in case that clock signal has long transition time, especially on the low frequency operation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.602-607
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• 1998

Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber material for design function. However, there are still a lot of difficulties in the understanding of dynamic characteristics of the rubber components in compression. In this paper, the dynamic characteristics of rubber materials for anti-vibration under compression were investigated. Dynamic and static tests for rubber material with 3 different hardness were performed. In dynamic tests, non-resonance method, impedance method, was used to obtain the complex modulus (storage modulus and loss factor) and the effects of static pre-strain on the dynamic characteristics were investigated. Also, a relation equation between linear dynamic and nonlinear static behavior of rubber material was discussed and its usefulness to predict their combined effects was investigated.